The theory of optical waveguides has been known for some time. Optical waveguides may be defined as a bundle of optical fibers each having a transparent core surrounded by a layer of transparent cladding material which has a refractive index that is lower than that of the core. Communication transmitted by light waves over optical waveguides is much more efficient than communication transmitted by conventional transmission means. Moreover, by means of fiber optic cables, vastly more communication channels are available than can be had on conventional transmission cables of the same dimensions. In prior art optical waveguides it was necessary to employ separate optical transmission lines, one dedicated for transmission and the other dedicated for reception. The present invention provides means for simultaneously transmitting and receiving on the same optical waveguide.